From: willy@linux.intel.com (Matthew Wilcox)
Subject: [PATCH] Remove redundant writes to uncached sqe memory
Date: Sat, 10 May 2014 22:52:54 -0400 [thread overview]
Message-ID: <20140511025254.GC6121@linux.intel.com> (raw)
In-Reply-To: <536D3E3F.9050902@micron.com>
On Fri, May 09, 2014@01:44:47PM -0700, Sam Bradshaw wrote:
> The memset to clear the SQE in nvme_submit_iod() is made partially
> redundant by subsequent writes. This patch explicitly clears each
> SQE structure member in ascending order, eliminating the need for
> the memset. With this change, our perf runs show ~1.5% less time
> spent in the IO submission path and minor reduced q lock contention.
I'm shocked! I thought that zeroing the cacheline first would be better
performing than storing into parts of the cacheline. But I can't argue
with your numbers. I think your patch is missing a store to the metadata
element though; care to rerun your test with that added?
next prev parent reply other threads:[~2014-05-11 2:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-09 20:44 [PATCH] Remove redundant writes to uncached sqe memory Sam Bradshaw
2014-05-09 21:14 ` Matias Bjørling
2014-05-11 2:54 ` Matthew Wilcox
2014-05-11 2:52 ` Matthew Wilcox [this message]
2014-05-12 19:41 ` Sam Bradshaw (sbradshaw)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140511025254.GC6121@linux.intel.com \
--to=willy@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.